Identification of selected metabolites of skatole in plasma and urine from pigs

During investigation of the kinetics of skatole in pigs, it was observed that some pigs, which are poor metabolizers of skatole (3-methylindole), are incapable of forming a metabolite named MII. This lead to the hypothesis that incidents of boar taint in Danish pigs could at least be due partly to polymorphism in one of the P-450 isoenzymes responsible for the oxidative metabolism of skatole. To further investigate the metabolism of skatole in pigs, selected metabolites of skatole were isolated and identified. Three major metabolites of skatole were isolated from urine from pigs given [C-14]-skatole (5 mg/kg). The metabolites were identified using mass spectroscopy (MS) and nuclear magnetic resonance (NMR) spectroscopy as 6-sulfatoxyskatole (MII), 3-hydroxy-3-methyloxindole (MIII), and the mercapturate adduct of skatole, 3-[(N-acetylcysteine-S-yl)methyl]indole (MX). MII and MIII are found both in plasma. and urine, MX is only found in urine.